In the field of lasers, the output developed by a typical laser device is a continuous beam. The present invention is a technique and apparatus for modulating the output beam. Most modulation techniques operate on the beam outside the laser cavity. Such systems are extremely inefficient, or have other disadvantages. The present invention operates on the beam within the laser cavity, and thereby overcomes the deficencies of those prior techniques.
There are other prior devices which, like the present invention, are intracavity modulators. Those known include both electro-optic and acousto-optic modulators fed by electric sources. The present invention includes a solid state electro-optic modulator utilizing the Franz-Keldysh effect. Its advantages include simplicity and dependability, and a very high frequency rate of modulation. The frequency rate of modulation is limited only by the physical limitation of the semi-conductor material and the highest frequency that can be imposed on the filter, the latter of which is more limiting. Thus, the operating limitations of the modulator are those imposed by the geometry of coupling the signal into the material .